Diaphragm for storage tanks



Aug. 4, 1953 c. P. KRUPP DIAPHRAGM- FOR .STORAGE TANKS 2 Sheets-Sheet l Filed Jan. 24, 1950 zz Enf'a. Mg-@LFE 7 /M El??- Aug 4 l953 c. P. KRUPP 2,647,657

DIAPHRAGM FOR STORAGE TANKS" Filed Jan. 24, 1950 2 Sheets-Sheet`2 Z0 l H' i f' f7-5 fili' Patented Aug. 4, 1953 DIAPHRAGM FOR STORAGE TANKS Carroll P. Krupp, Cuyahoga Falls, Ohio, assigner to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application January 24, 1950', Serial N o. 140,237

(Cl. 22o-85) 6 Claims.

This invention relates to diaphragms for tanks used for storing liquids and is especially useful in storage tanks for oils, and the manufacture,

installation and use of the diaphragms.

In the storing of liquids where it is desirable to protect the liquid from contact with the atmosphere, as in the storage of volatile petroleum products or other low-boiling liquids subject to loss by evaporation, or in the storage of liquids containing ingredients which might unite with moisture in the air to form corrosive acids, as in the storage of some crude petroleum oils, or in the storage of liquids which may become oxidized by contact with air, such as vegetable oils, it has been found desirable to provide storage tanks with a floating cover. These covers sometimes have been of a complicated construction and in other cases have been merely on the order of flexible floating diaphragms.

` In constructions heretofore proposed, diiiiculties have been encountered, especially in that it has been difficult to seal the diaphragm to the walls of the container and the materials often have been damaged in securing them in place. Furthermore, it has been difficult to position the diaphragm properly before securing it in place.

It is an object of the present invention to provide an improved manner of securing the diaphragm in sealed relation to the walls.

Other objects are to provide protection of the margin of the diaphragm against accidental damage in securing it, to provide facility in properly mounting the diaphragm, to provide a reinforced attaching margin, and to provide for convenience of manufacture and assembly.

These and other objects will appear from the following description and the accompanying drawings.

Of the drawings,

Fig. 1 is an elevational view of a liquid storage tank constructed in accordance with and embodying the invention, the lower part of the container being shown in section and the container being partly lled with liquid.

Fig. 2 is an enlarged detail sectional view thereof showing the diaphragm in place before being sealed to the container, one portion of the diaphragm being turned back to show the construction, parts being broken away.

Fig. 3 is a view like Fig. 2, but after the diaphragm has been secured in place.

Fig. 4 is a perspective view showing the apron and cushion strip in the first position of assembling them.

Fig. 5 is a similar View showing the apron and cushion strip in a subsequent position of assembling them.

Fig. 6 is a perspective view, partly broken away, showing the diaphragm with its apron and cushion strip assembled and ready to be placed in the container.

Referring to the drawings, the numeral IU designates a cylindrical storage tank of metal suitable for application of the invention, having a closed bottom I l and top I2. A pipe I 3 connects with the bottom for supplying or withdrawing a liquid I4. A pipe I5 connects the top of the container to the atmosphere for venting it.

A ilexible diaphragm in the form of a bag I6 having a bottom wall and continuous side wall, telescopically reversible on itself, is secured to the side walls of the tank or container at a distance above the bottom of the tank, as at I'I and for this purpose an upwardly open channel is provided at the inner wall of the tank as by welding an angle iron I8 thereto continuously thereabout with one leg I9 of the angle extending vertically and the other leg extending horizontally to provide the floor of the channel.

According to the invention, to provide for supporting and reinforcing the margin of the diaphragm, an apron 20 of impervious material, which maybe fabric reinforced, is secured to the bag I6 in extension of the side walls thereof and in overlapping relation to its upper margins. This margin is preferably additionally reinforced at the upper margin of the apron by a cushion layer 2| of heavy impregnated fabric.

To provide for accurately positioning the margin of the diaphragm and to facilitate securing it to the wall of the container at the retaining channel iron I3, the apron and cushion are united and preformed with a reverse bend 22, thereby providing a hook-like fold Za circumferentially of the apron for positioning over and seating upon the leg `I 9 of the channel I8. With the hook-like fold resting on the channel leg I9, the remaining margin of the apron outwardly of the fold 20 within the channel, a strip 23 of suitable material such as lead is laid within the upwardly open fold of the apron margin and is caulked in place as by a hammer and caulking chisel or other tool. The caulking thickens the strip of lead laterally and ts, clamps and seals the margin of the apron in the channel. In this caulking operation the fold 20a. of the apron seats upon the channel leg I9 and owing to the preformed and vulcanized condition of this fold it retains its position on the leg so that it will not be dragged over the leg during the caulking. At

the same time the material of the apron for fitting the inner surface of the channel is supplied by the margin of the apron outwardly of the fold, as will be seen by a comparison of Fig. 2 and Fig. 3, which action greatly facilitates the caulking and fitting of the apron in the channel without objectionably distorting, wrinkling or pulling thev diaphragm or otherwise injuring it in the caulking operation The cushion layer 2l is for the purpose of preventing damage to the apron as by hammer blowt t may be made of heavy belt duck., Thelduck is frictioned with material such as Va rubber'trnaterial having low expansion propertiesin 'thefpres-v ence of petroleum solventsto preservethefabric and render it liquid tight. The rubber material commercially known as Nipol rubberl has given. good results for this purpose. The outer faces'o'f the duck are coated slightly with the rictioning.'

material, the coating preferably being Such aS would result-from frictioning without applying'a skim coating.

4For Abest, results, the apron'must-permt'exing and must reinforce the diaphragm and present resistance to wear, while "at the same time it should remain impervious to the liquid to be stored; 'It is also desirablethat it have resistance tog'corrosivesolutions,such as acids. A layer of nylon fabric of about eight ounce weight has been found satisfactory when properly impregnated andjcoat'ed, The ,fabricA is first frictioned and coated with the rubber composition. rEhen a barrier layer of liquid nylon may be applied over its surfaces and a'protective coating of rubber-mai7 then be applied thereo'ver and cemented thereto. This construction is particularly'resistant to gasoline'or other light petroleum solvents.

The bag I6 of the diaphragm/may be of any suitable iiexible sheet materialresistant to action of the liquid, such a's a suitable rubber or plastic composition' or a blend thereof.

jIn forming'and assembling theapron and its cushion, strips of these' materials `substantially equaling in length thecircumference of thetank are folded upon themselves longitudinally and are then superimposed as shown'in Fig.` Liwith'a layer'of adhesive material therebetween as' atf35. The flap'. 3 6is'thenfolded to the right'of vthe flure 'about .thef strip A'Z' l 'and adheredtheret'o. Then the `flap.3fisi-folded about the stripZii'and adhered'thereto asshown in Fig. 5. The vends-'of the apron .and'cushionlare steppedwth relation to each other and thesestepped ends areithen joined towprovide an endless apron. This apron is then subjected to avulcanizing operation and then is adhered as at 38 to the bag U5 of the diaphragm, an adhesive material preferably a vulcanizable cement :being used which will vulcanizeuponapplication Aof heat and'be resistant to' solvent liquids.

After, the diaphragm is in placein ythe tank Aa liquid 4i! ,may be applied over the diaphragmfif desired, although, that is not necessary. This liquid when yused acts as a lubricant :between the folds of the diaphragm and also as a Weighting materiel,

fVaifations maymb'e made without departing from the scope ofthe invention as it is defined by the following claims.

XIl. A diaphragm for a storage tank comprising a covervportion andan apron portion labout said cover portion,` said vapron portion comprising flexible sheetmaterial, having a circumferentially eX-' tending reverse fold Apermanently formed Ain said,

material of a shape to hook over the leg of a retaining channel on said tank to position said diaphragm relative to said tank, and said apron portion having a margin of said material outwardly of said fold circumferentially troughed for anchorage in said channel, said troughed margin providing an annular space for caulking material under 'compressi-on between the sides of the troughed Iportion..

2. A diaphragm for a storage tank comprising `acover portion and an apron portion about said cover portion, said apron portion comprising iiex- "iblesl'i'ee't'niaterial having a circumferentially eX- tending reverse fold permanently formed in Said material of a shape to hook over the leg of a retaining `cli'annel on said tank to position said da- ;phragm relative to said tank, said apron portion having *a margin of said material outwardly of said fold circumferentially troughed for anchorage in said channel, said troughed margin providing an annular space for caulking material under compression Ybetween the sides of the troughed portion, and said-apron-portion being of increased thickness-in the region of said circumferentially extending fold-and having a fabric 'reinforcing cushion in saidregion.

3. Adiaphragm for a storage tank'comprising a cover vportion of flexible sheet material and an apron portion about said cover portion, said apron portion comprisingV flexible fabric-reinforced rliquid-impervious sheet material having a circumferentially extending reverse fold Apermanently formed-in said material of a shape to'hook over the vertical Vleg of a retaining channel on said tank to position lsaid diaphragm relative to said tank, and-'said apron portion-having a margin of-said material outwardly of said'foldcircumferentially; trou'ghed to line said channel'in an upwardly open fold'to receive'cauliringmatee rialyand a layer of reinforcing-cushion material over thetr'oughed area/along said margin said folds and'secured tothe-material of "said-apron to providefre'sistance tocaulking. pressure.

e'. A Vdiaphragm lfora storage tank, :said -diaphra'gm compris'ing-a'cover portion and 'a'e'xible apron portion; comprising acircuinferential `rband of coated fabric about the coverportion and-pro viding` a wear-resisting margin thereof, Said apron portion having? af'reversely folded circuiilferentialmarginadapted to'hookfvovera leg of a channel abo'utth'ewall` of the'tankfand providean f2 anchoring trough 5 for caulling materiaL- cushioning layerof material within the folded portion -of the 'apron portion providing-a' protective layer thereabout and deformablecaulkng means ywithin said folded portion' in contaetf'with saidcushionin'g layer forciamp'ing the apron. portion in said channel in sealing engagementtherewith.

5. A diaphragm for 'a'storage'tank .Saiddiaphram'comprising a cover portion Aanda lflexible apron portion! comprising 'a Vcircu'i'nferential band of coated fabric about'thecoverportion and providing a `wear-resisting margin-thereof, said yapronportion having'a Yreversely'folded circumferential margin Vadapted to hook' over the leg of a-.channel about the walliof the tank and provide an anchoring trough `for. caulking materia-l, a :cushioning layerof rubberZ impregnated beit duel; witiii'nfthe foidedportien Y@f the' apron portion* providing a protective layer thereabOilibm and deformable `caulking. means within said folded portion in contact with vsaid cushioning layer forclampingthe apron portion in said channel in sealing engagement therewith.

6. A diaphragm for a storage tank, said diaphragm comprising a bag-like cover portion of flexible impervious sheet material and a flexible apron portion comprising a circumferential band of coated fabric about the cover portion and providing a wear-resisting margin thereof, said apron portion having a reversely folded circumferential margin adapted to hook over a channel about the Wall of the tank, a cushioning layer of rubber impregnated belt duck Within the folded portion of the apron portion providing a protective layer thereabout, and deformable caulking means within said folded portion in contact with said cushioning layer for clamping the apron portion in said channel in sealing CII CARROLL P. KRUPP.

deformable means References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,669,183 Wilson May 8, 1928 2,142,225 Weichsel Jan. 3, 1939 2,257,941 Ellis Oct. 7, 1941 2,371,632 Lippincott Mar. 20, 1945 2,378,467 De Kiss June 19, 1945 2,380,866 Overbeke July 31, 1945 2,387,598 Mercier Oct. 23, 1945 2,578,090 Plummer Dec. 11, 1951 

